1. Field
The disclosed and claimed concept relates generally to nuclear power plants and, more particularly, to a method of replacing at least a portion of a shroud employed in a boiling water nuclear reactor, and to an associated apparatus.
2. Description of Related Art
As is generally understood in the relevant art, a boiling water reactor (BWR) is a nuclear device which generates steam for the operation of a steam turbine that typically operates another device such as an electrical generator. A BWR typically includes a reactor pressure vessel (RPV) within which is disposed the BWR. The BWR typically includes a plurality of fuel assemblies that are surrounded by a shroud. The shroud is of a hollow and roughly cylindrical shape and is supported on a shroud support plate within the RPV. The shroud is configured to retain coolant around the fuel assemblies in order to cause the heat generated by the fuel assemblies to be converted into steam via evaporation of the coolant. A set of jet pumps typically keep the coolant in a state of motion and agitation in order to promote heat transfer from the fuel assemblies into the water to form steam.
While BWRs have been generally effective for their intended purposes, they have not been without limitation. For example, it has been observed that as the hot operating time of a BWR increases, cracking has been observed in the shroud. Over time, such cracking within the welds used in forming the shroud and elsewhere have become sufficiently extensive to require replacement of the shroud. However, such shrouds typically have been assembled by welding their components together and by welding the shroud to the shroud support plate and possibly to other components. As such, replacement of a welded shroud has been difficult. It thus would be desirable to provide an improved method of responding to the cracking that has become known to occur over time in the shrouds of BWRs.